The body/chassis of many mass-produced motor vehicles is/are fabricated for the most part as an assembly/assemblies of electrically conductive parts, particularly steel. It is common to ground electrical components in a vehicle electrical system to such conductive parts of the body/chassis. A ground connection to the body/chassis may ground single or multiple electrical components.
A known ground connection comprises a ground terminal on an end of a ground wire or ground cable fastened directly to an electrically conductive part of the body/chassis by means of a fastener such as a screw. When a ground connection must be capable of carrying a significant amount of current, it is especially important for the connection to have a sufficiently large area of contact between the terminal and the body to minimize the electrical resistance of the ground connection. Because a vehicle may be subjected to extreme operating conditions such as repeated operation over rough terrain in hazardous locations, it is also important that the factory-installed integrity of a ground connection be maintained for the useful life of such a vehicle.
An eyelet on the end of a wire or cable is often a preferred electrical terminal for grounding an electric circuit because it has a large surface area that can be forced flat against a vehicle ground by an associated fastening. One example of such a fastening comprises a threaded ground stud on the body/chassis onto which the eyelet is first placed and then forced against an underlying ground surface by screwing a nut onto the stud and tightening the nut to force an underlying surface of the eyelet surrounding the terminal eye flat against the ground surface. The ground surface may be the body/chassis itself, or a part of a component, such as a bus bar or terminal strip, that is itself attached to the body/chassis, and consequently a ground stud may be one that is attached directly to the body/chassis or it may be part of a component that is attached to the body/chassis. Examples of such components are bus bars or ground strips that commonly have multiple ground studs that provide for the ground connection of multiple ground terminals to vehicle ground.
While it might at times be possible to stack the eyelets of multiple ground wires/cables onto a single stud and then screw a nut onto the stack and tighten it down to force the stack against an underlying ground surface in order to minimize the size of a bus bar or ground strip, such a practice may in certain circumstances be less preferred to the practice of fastening only a single eyelet at each stud.
The use of an eyelet is desirable because, unlike a fork terminal, it cannot come off a stud if the nut merely loosens without coming off the stud. Both types of terminals are however prone to turning on a stud, and while the ability of an eyelet to turn on a stud may at times be an advantage when a ground wire is being placed onto the stud, it may be a disadvantage when the final tightening of the nut occurs because that final tightening may also turn the eyelet and wire/cable to an undesired circumferential orientation on the stud, possibly stressing the incoming wire/cable.